SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '346e731d2b292cbda4fc25bc168badbc22958842eeee4883511a06ff6aeb515f' 
  AND token = 'DFvuZ9rnT6L0NRRyZtm2H1TSU+DliCGldU+rrqyu01I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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