SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb9af5b9559d40ed68b2751e75ae64605601896d4e9c9117e80dfb534a84d95b' 
  AND token = 'FlQn7UYMJLiidslCToxRiLENn350dFnO3zRXgBVRbhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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