SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d596b8006d240dcc42fe356613715dc2d56ae30db8eb7bb23974a9f4aced5c7' 
  AND token = 'uzl89PUwW+VCXzsPqFQiLd+rx4nYxXVWRInabTFCtkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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