SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99017c0db3cf042647528d81117104a695489912c236958659c5d2dcb866b225' 
  AND token = 'eTtlvPaEt9F/z7lxQz4SGmBHIqtBWqCnQZuOdeODaXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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