SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4a7318eb5a002277885fffff28a6cb3f78286f06b6ad5565a3a1d2404fb0442' 
  AND token = 'Vnq3y/GhZQZ7/Kbo/Pd6lE0AfojA2WgjA+nQpHOH9k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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