SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ee4fe461254b4882922e6398f4c421ede352c33ea3abf9dc7de5ad45cfc090' 
  AND token = 'YhAQUKmGUjR3VbDMsNgh59mIx6Qg+TDzuXOltIZeOj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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