SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37812ece6b78f25198b4a4a41ac1d46dd87d31a7249f77598845c99f643ed9f1' 
  AND token = 'uiuBt+aitVpDHY4e6TSx7IIqXKzsdEceH66w7TLfOjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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