SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2edd1cf1388e8b4a3b2b4015751043adf7afc6da3618d9eea809c9a1012fef90' 
  AND token = 'fXoKma+NSzIyV+9PnYGB2EeE+5gmqf91o40I7f7m488=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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