SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffb98284fc10857f5c317f7471b2b07c31f472e7663d22e6662b9434ddc2f4e7' 
  AND token = 'D5tLkjBKCttS2uSjmvu9qAkI0jg6OVoh+53ugMjYYO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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