SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3a7f5cd368903f7bb413e7737963e841a8e4ca20b000b066b41d5d3635106874' 
  AND token = 'WzcFO+9R5fXEpMXO/QXpIv94irQZXByvWCIKWlrveDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}