SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db4c965a80f522286dff3a4ad33d611258c662741c5eb6e368d7e069357eeadb' 
  AND token = 'lCtr8FVGIKue/A5lFNu/WBBTsxIsto3swYFcm7aWWd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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