SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e6b614b20f0519b8bab149bcbd7544351ce1d3fde0fce2804b93bb233cdf347' 
  AND token = 'XxUuLhymYZw4YWVTeLr3SfgfSBtyYTN00ZNN2/ATwsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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