SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dda1f084727f707310817e76833e4cb26dea7bf0a6561fd936e49632983c150' 
  AND token = 't3hcX6hZJ7vgUKFWZk/ZUDczEsBe5bbSkDPeTt3tsZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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