SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eec1bda55b40c6ecf79f94843540169a0ab5ca620f7528cb4144d4531047b69e' 
  AND token = 'sPKQoONa4nJydFbWYlAoqymGMPX5IGRpHUljIuapxN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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