Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af8fe75302ca209151ef103888a6fa2de06795d5c1bbc5b53628ee32ef37f24c' 
  AND token = 'r4SUp86GXbCiRfmmWPRLgJWwC2YmjOBgFvXAQaeg/6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}