SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d22108eee127e57ef5dd170b6afec734b622c615edcdeddb01b457ff3880559' 
  AND token = '7vYAI/p958hlZ5qB7wAaPCE2Imt8QgVrh7hFNC1Rkt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}