SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc7a5eda3c8fc52875f795d8ed1683e102efe6684f6b2e012a00d2a87c3bfbbf' 
  AND token = 'OeCbt1JNur7gtW4pQvk3E5SK97SdIkN/VHxSijzGP8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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