SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ec839858d0bb0249a140cd6de6442a23fff9833cedabb9c01ea37d7dc5f6905' 
  AND token = 'RDqYMpq/K7/ue1Xf/OsM1ZhqJtYRKWKZs7vNEwMFvwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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