SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60c6d84bc6802ffad21e9e990dbebb23626821b490b6789b4c400d5f76f6382b' 
  AND token = 'q+3rXz+DUAKXeE7SHuxh5KeCX98IDPGOdP/l9yhRfCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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