SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8abb6dbf0590f3139a682888ca59267a6a61d95096c5a3a0e138b7f171aac4a0' 
  AND token = '37FWy++5NsQuxRILp4SAINoeV5GYB5630CuQcwH+tQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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