SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9980e144da9eeb49c56fc812484f27cd3422fad5351f196e67445ff5e69a3fb' 
  AND token = '6utLDUOSq/fCAAkIks+kKkMKgWZUZXm+UMHXwnD8J9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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