SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387faac6e3b73ab9e40399bc18b79ee9afbb2f1efd1b03ab17c341723ecc66fe' 
  AND token = 'sotdxmfHiST1i8nX0DiSIkwyOEfOPjqUh0LymbtAJ78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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