SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ebd8820b7fba5ac5b8c34826241464cd06a5df9c0409614d274f98fb71eb3c9' 
  AND token = 'lwZz/rGfGxk5CyRjDSfFdiP/wTF1m+qNE3jgzJ2FToM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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