SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ab4a2444a7cdda6dfdfaf04749765615b83ef6259090400d1cb1a7a57a29d8' 
  AND token = 'YmMuW6oivDUhLB90iAxpRxFCnUylTItTzKZoT9cmdHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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