SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e027f4782b3b590cc07d0c89d02507b5373a450b75537571f0286a7380ebfad0' 
  AND token = 'MZyh4t0J1GAUZhUMxsOqrVZvw0TzL98Fm82AEynbsHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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