SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '466a780ca52fb84fd0159b182b04a814e3457f8575b321cf994450a104d5689b' 
  AND token = 'xAhNmkRLxFB4+2ovHxiVdFjGvPcYxA408X2AHzi6Z5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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