SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd27390768da4faf782d3de9da049f1db3cf45f769bef97a45a2eedc79d3f87' 
  AND token = 'A8m/NliNXvekel6xXrq+FC2UJkftPbVAgWBpTInSprc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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