SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6f1a20a94a1347f3734161d3b5b2d7e5facb46510c2e2fa23c71a9ab752a169' 
  AND token = 'UNXRp1RHk3JmpzENRgkWpLV1pJKGS2bgJONBKlKkFok=' 
  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"
    }
  }
}