SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cb718158831eea59e604ddcb48afc74edb30139eadbb5e1b8bd803d72890655' 
  AND token = 'vEVrmindW+RBkq/ir0GIPp4MhzpH7bO2iIE3j+y212E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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