SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2251b104b595e82076dd51a56487358c62126d3a6233bb312b62dad240754fe9' 
  AND token = 'ozeVJ7XaMdi7Am5hLDOFgMvFEUN/aVNRu2FY/ycOoLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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