SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd5f293cb0e7ce9570c325d034cba36274bfd7657c6f5edb1fa691e8627addc' 
  AND token = 'mOBzXlGXcLgeS3HOsNsKfNs1j/4COmPq8ZOQB7pEQTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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