SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a10813d6daaee1f38bdb99c6a266909abe1ebb0a9d6a2a35684e253122ad2369' 
  AND token = 'GCKQEiweYate5OpMkHANFDpEqSBaYBUUvKWOzsbiVvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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