SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bac70f594a9ee41b9c236c38bc403f18fbd2ee0de2fd1841fb131a44c8f1afb3' 
  AND token = 'PyoWMoAIMkygzZ+lLdxKs74uK4Jz8YeGHr7BzNB0QKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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