SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '136be37e0a22cd22efcc6a1e7316e3b00d3e2081f2becfca3717278fcfd163b0' 
  AND token = 'hMZOpOQXLeFLYau4BHIrgIsSC8XhBhLMZi4kTBw/uGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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