SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc815a2b532fb6e745f26609f6d7322648eb279409d978ec5c041002105a3c7d' 
  AND token = 'bDZj34PdnXJORLFNv6VqGi+Qhv5TimxTYVF2TQdkJOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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