SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6885e268f0b497e0a3184307866e2aedbd11f1257d53d3dea20dd398b5bb91c0' 
  AND token = 'l5iQTlG73EGODGw0Jzh7AjuSjMzu1hLDIYziaLwXLB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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