SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a584a326999c4a13f2a631d398775eda0e7ff6c0b33ca2b18b97f35d931bb8' 
  AND token = '/6YNU2BYnytssW6hSfL1oGHmc1g3zRq3VdCqZGQ06Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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