SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '102f643ae05906cbe92995bc2244ad69a104e586492ec0758f876a2efda85d3d' 
  AND token = 'aBxgq3Y1XzhcAWfgig47C7UMMYxoKajQv5/cH1PNrV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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