SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09fc298e21134dfc81e8dbd19d5e7cc7230b92f2b3d0c0fc5bef25636d03a6a4' 
  AND token = 'XQgCizWLo+XUJV5fqp5IiyZkNfdv/fxvtd7328YmIXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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