SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91c3d6c189515a8fafecb704eb103012436a548d2fc3f35ee13d17a77218803' 
  AND token = 'Oeo7tL2+KtTPWw9HugrIDG/dWH6HRlIsM2IwRnEGzFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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