SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12877d63d513f7159f19c35d3f86442ca2774b82ba697c4d0259f52213c8c665' 
  AND token = 'bDugAiB4pLE3lUtG2INjUul4AHg+mwq9BSpWec05nJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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