SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21b4cd5a8d17ef3e8dc810f125b6cdc933d376523720d9c3f3f182b76c8a143d' 
  AND token = 'l5fXsvq6+6SW3sXWYNEBUSk3S0gRfSPEsuFLvBgmaHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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