SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90331ef63f82795d0b4a4ebafba8eb2f9e7eabab37dc876aa0c9948f9c8685eb' 
  AND token = 'VeHmFEl6nguaNoEDjvsmwDi3FRqgMPSQeuOGF+5hXZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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