SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72f2225cea5a32b884d54963d0828841cd1bc07c54b1eae2d9afc5066847b0b6' 
  AND token = 't9L1BJCZAwBZRGYoHSmvVn46ENtxt1rKgKP0snVldoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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