SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27e6e66de192b8c7ff6585e01c8836263c652c16aaec2c90a138f3950ba4fa32' 
  AND token = 'gwdioFLlsDiB9FIMi/5ItLPJV63ULuRQofkOcRWCIxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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