SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09a21dab3364d0f86d33bd512523a9a1d0ffde1516dc01549c6a88ec0259bc26' 
  AND token = 'DRNjT+5HVpMclYXDtSbQr3U2S8f23Pq6NeXoWfnUGWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}