SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33a03a7f96aa25ab0ed2b8391422033d220e796dcd13f0159ee5e81b9e607c85' 
  AND token = '2vasXfAOHI4yXpcs84yHLtfV06kdOR/J17a1g8+ewPc=' 
  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"
    }
  }
}