SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75d7be8adee4ee5beb9254f0ce735ac8a41e0d9cd3579b90f37036e9845035ed' 
  AND token = 'vClo79Ku/PNAnaxps+T4Q8jtdvI9NhCtISreBKKnNIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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