SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff2b077d2e5b45908ac9c3b086cc1d650dc4933821a04ab8768748ae438a237a' 
  AND token = 'rQS7xYn+fJfs4bn6skEjeDvMpwz1KqmOsIBfRG+TLJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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