SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9647bebd84b0eefad51acaa0690f992e87bb446e38d1dd8ea232b7da218ddaad' 
  AND token = 'U+F9CEJ946hYq6F8A0IcQ/9mGj6RRrbOgDT8u+nzOl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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