SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f2abe2c323c54680af94614a620809f79808dd35d92db1215e7e877a86c86ea' 
  AND token = 'sotmsIKYUDY3zNbLvpMVCJdUofRlHP2QOlW1jR9u2IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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