SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e87a48237799ea73dbb60d2ac005c2555c9628e038b5f3da745c299151ce5c3' 
  AND token = 'OYtUuF7l0Els5IpFgHIp0GLOFtA4H3+EpEhtuWrjOEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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