SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019270f8404877a31e2f6f9dad43a9eefbed55a39794eca0555a749340d5f6cb' 
  AND token = 'fhcB2pMN+75gohwzhlq7nCDszjdZsDJatFrCOJ1rcqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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