SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3154a7955f8d483f60850404e34062e4ef04cae32626d3eb0d059813d08d1c' 
  AND token = 'g90Iubq7FXmZQ8HQ5VZtoSOhxSbzN3WHMPRyUkzVnDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}