SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3651581edbf5c12e555c629863e20a2815bfe215fb98b3a0d64ccd968981fd33' 
  AND token = '0L+IVWjwg0kGQzVqhgB0DuKrt2N3nT4DMnH9YHv9Sfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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