SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a4dc01db07c6a9f9ffea5d9106594c29f1b2b8437ad4824ecb82a93a893cada' 
  AND token = 'qEYx1n8d6PsnAkQJRPEOtv6JsZtctDk0mH5aqnEk6Xc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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