SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e13c3b46c091cc3c4a4e312296b71e094daf3a1512e564c122d64651338c9be' 
  AND token = '4JRepgke/k9OLrptnzn4Udu8QzpoQ3eSCsdl4q+7d2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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