SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3843b8b7503225c5fc52b60d463737803eca584e31020729bc017362882286' 
  AND token = 'kKJNVv57eNWcGXKwfVLYUBT2aCKDLQc1u3voAc7StdM=' 
  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"
    }
  }
}