SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a4bb01cbb34126f7957ef677b3a454ee50affb6f16e784514a5145bcdac3c9f' 
  AND token = '6Wh/9PG9DJjh+J0NJYpBtd0rvNZ56JOqvYR3Qn8Pi0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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