SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9551ba44456998899d2463697880bcd9ca50d53eb3ece4a6824b7e8f5e40460a' 
  AND token = 'HVEbD+UrXCq5/veApBAwLbojgNWIhRB+A4xhlMJgwjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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