SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44a8dd9413ffe4081ae8de999ec61c5bfbc0ef363c6f0e8527600d542920c983' 
  AND token = 'fbh5IPUKYMvgyMUjieGucQ/EMKvfKEudVNJe+9zCqkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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