SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a953cb26934aa1422093135d3eac46109221db6418f254fc62802b608a14075d' 
  AND token = 'm1HPn+NtqoMrJEs9qqZCcFvmbwRG3Kdt58wnJneXpWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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