SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f5692f27192fc36be1b7ac7d1e1c6ab5754775605ba7e21f1f0261e3828ab8d' 
  AND token = 'HavZXNnKXCjqmgmJBfdQPGkjm5M2eukupVG4WClGjDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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