SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9663f568a288c55c4bf92e841e2daa3bc48728689c77ed0dae14bb414787ac' 
  AND token = 'eRrBWFhlyoPyoTuyRq1KadiG678eDMmcCDFXKJFf96I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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