SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '735d2efcdac5e96e6b8fa793644dd28d979e3029f4de3b808e452dfe6ba5b00a' 
  AND token = 'MCP21o/5OKLwxTagKcVZhKLW1epz2HprrYRPxmv/vK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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