SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a841103d8657ba1584cf88e8e19a0f2966614b6099b23fd9ccfe3b4ddc295ed5' 
  AND token = 'aPUFO0kSVnxLEmEyYqW3bge0Ot7znyBUI+6m23rub/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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