SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b75480755b59440e22744141199d76743e56ba2e2478cbe88aed9901a104acea' 
  AND token = 'G4Al3IjZMifpYjp4zktU+RNwBbA7b3RxDFnyZVudbik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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