SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '436644bbb4184cda7120b543e2561beabd7040d71e44afd6057b959b3212b8c7' 
  AND token = 'JBcXPoqLLW1nT5iPjCjPOLJVZA8g3PQQ/Zz+8oJn7HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00127

JSON explain

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