SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e1e43d0bfbd433e043ecbc1557c33930d268c4512d345d35d1b97a728527a9a' 
  AND token = 'PXMilBZDvp9lJ3SEg21fX5grKW3YRKNADUbcIWHZnEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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